Locking mechanism for live mathematical documents

For use in a live mathematical document program executed on a computer processor, the live mathematical document program capable of editing and processing a live mathematical document, the live mathematical document program enabling a user to enter mathematical expressions in any position in live mathematical document and automatically updating the live mathematical document to ensure that all expressions are consistent with all expressions upon which said expressions depend, a system for locking a defined portion of the live mathematical document, comprising:

• means for positioning a first boundary line and a second boundary line in the live mathematical document, the first boundary line and the second boundary line each comprising a horizontal line across the live mathematical document;
• means for locking an area on the live mathematical document, the locked area being the area between the first boundary line and the second boundary line;
• and
• an editor for editing expressions in the live mathematical document, the editor including means for ascertaining whether an edit is within the locked area and means for disallowing edits within the locked area,
• wherein expressions in the locked area are automatically updated by the live mathematical document program to ensure that all expressions in the live mathematical document are consistent with all expressions upon which said expressions depend.

For use in a live mathematical document program executed on a computer processor, the live mathematical document program capable of editing and processing a live mathematical document, the live mathematical document program enabling a user to enter mathematical expressions into the live mathematical document and automatically updating the live mathematical document to ensure that all expressions are consistent with all expressions upon which they depend, a system for locking a user defined portion of the live mathematical document, comprising:

• means for positioning a boundary in the live mathematical document;
• means for locking an area on the live mathematical document, the locked area being the area determined by the boundary;
• and
• an editor for editing expressions in the live mathematical document, the editor including means for ascertaining whether an edit is within the locked area and means for disallowing edits within the locked area,
• wherein expressions in the locked area are automatically updated by the live mathematical document program to ensure that all expressions in the live mathematical document are consistent with all expressions upon which said expressions depend.

A method for disallowing modification of a portion of a live mathematical document in which at least one expression is present, comprising the steps of:

• in response to prompting by a user, positioning a first boundary adjacent to the portion of the document that contains the expression;
• in response to prompting by the user, positioning a second boundary adjacent to the portion of the document that contains the expression so that the expression is disposed in an area defined between said first boundary and said second boundary;
• locking the area defined by the first boundary and the second boundary so that the first boundary and the second boundary cannot be moved;
• disallowing editing of the expression within the locked area;
• and
• automatically updating the live mathematical document when an allowed edit occurs to ensure that the non-editable expression within the locked area is consistent with all expressions upon which the non-editable expression depends.

For use in a live mathematical document program executed on a computer processor, the live mathematical document program capable of editing and processing a live mathematical document, the live mathematical document program enabling a user to enter mathematical expressions in any position in live mathematical document and automatically updating the live mathematical document to ensure that all expressions are consistent with all expressions upon which said expressions depend, a method for locking a user defined portion of the live mathematical document, comprising:

• positioning a first boundary line and a second boundary line in the live mathematical document, the first boundary line and the second boundary line each comprising a horizontal line across the live mathematical document;
• locking an area on the live mathematical document, the locked area being the area between the first boundary line and the second boundary line;
• and
• editing expressions in the live mathematical document so that an edit that is within the locked area is disallowed.

For use in a live mathematical document program executed on a computer processor, the live mathematical document program capable of editing and processing a live mathematical document, the live mathematical document program enabling a user to enter mathematical expressions into the live mathematical document and automatically updating the live mathematical document to ensure that all expressions are consistent with all expressions upon which they depend, a method for locking a user defined portion of the live mathematical document, comprising:

• positioning a boundary in the live mathematical document;
• locking an area on the live mathematical document, the locked area being the area determined by the boundary;
• and
• enabling a user to edit expressions in the live mathematical document;
• ascertaining whether an edit is within the locked area;
• disallowing edits within the locked area;
• allowing edits not within the locked area;
• and
• whenever an allowed edit occurs, automatically updating the live mathematical document to ensure that all expressions in the live mathematical document are consistent with all expressions upon which said expressions depend.